Which causes the thermal energy in a building to decrease?

the air conditioner and the heat engine
the furnace and the heat pump
the heat pump and the air conditioner
the heat engine and the furnace

The thermal energy in a building decreases because of the heat pump and the air conditioner.

The thermal energy increases because when the temp increase and it decrease when the temperature goes down. The air conditioner takes in heat and makes the room cooler. The heat pump works both ways, in winters it acts like a reverse air conditioner and in summers it works as an air-conditioner